The invention relates to a machine for collecting and pressing an agricultural harvest or crop, for example, grass, hay, straw or the like, to roll-shaped bales. The machine comprises a winding chamber that can be opened, wherein the winding chamber has a bale-forming device arranged downstream of the crop collecting device and guided across at least a first and a second stationary deflection devices. During a bale-forming phase, the bale-forming device travels within the winding chamber along a spatially determined movement path on guides. For compressing the bale to be formed after reaching a maximum bale diameter, the bale-forming device exerts on the bale a compression force in a direction from the exterior to the interior of the bale.
In customary configurations, machines of the aforementioned kind for collecting and pressing an agricultural harvest or crop are designed as round balers having a fixed chamber configuration; they have a bale-forming device that during the entire bale-forming phase travels along a spatially determined movement path and, for this purpose, is guided on guides provided on the housing. With such machines, bales of a certain bale diameter can be formed in that harvested material is supplied by means of a crop collecting device to the bale-forming chamber and, after filling of the provided bale-forming chamber, the bale-forming device exerts a compression force in a direction from the exterior to the interior onto the bale to be formed so that this compression phase is carried out subsequent to the preceding crop supply phase and the bale forming phase. With such machines, bales can be formed that, as a result of the bale compression phase provided at the end of the bale forming phase, have a relatively hard external diameter area while they have at the same time a relatively soft bale core. This can have advantages for a subsequent processing of the bale in that the relatively soft bale core can be divided with simple means and also without great force expenditure.
Moreover, it is disclosed, for example, in U.S. Pat. No. 4,549,480, to design machines for collecting and pressing an agricultural harvest as baling presses with a variable size of the winding chamber; in such devices, starting with the initial bale-forming phase, the bale to be formed is guided constantly on the bale-forming device by means of a spatially variably moved bale-forming device so that the bale-forming device, even during the entire filling process of the variable winding chamber, exerts a force onto the bale and a subsequent compression phase is thus not needed. Because compression of the bale is carried out continuously, the bales are ejected at a desired final diameter range of the bale in a finished state from the bale-forming chamber; it is therefore possible to produce bales with different diameters and thus with different sizes.
A bale that has been produced on such a variable machine differs however with regard to its configuration, for example, with regard to the stiffness of the bale core, from a bale that has been produced on a machine that operates in accordance with the fixed chamber principle. A bale that has been produced on such a machine with variable winding chamber is therefore different with regard to its break-up properties from a bale that has been produced on a fixed chamber machine. A disadvantage of machines that operate according to the variable bale-forming principle is moreover the high technical expenditure in the form of the constructive means that enable the variability of the bale size and a permanent force action. Moreover, with such machines it is not possible to form bales that have a relatively soft bale core.